I'm thinkin' both--but way less pity and way more revulsion. He is in control of his behaviors and he chooses to transform himself--in a very short time, I might add--from a loyal soldier and subject of the King to a murderous, treacherous usurper. I know we're supposed to feel pity and awe in a tragedy, and I do feel some sense of pity for him in the end when he realizes the witches' predictions have given him a false sense of security. Other than that, though, he behaves in despicable fashion against lots of innocent people who are simply in his way. Nothing very redeeming in that.
In tragedy, by Aristotle's definition from his Poetics, the reader must feel pity and emotion--some critics suggest compassion and awe as better terms --for the tragic figure. However, although the audience feels this compassion, they are not dejected by it. With the fall of the hero and his gain in wisdom or self-knowledge, there is, besides the sense of human waste, a fresh recognition that life has unrealized potentialities.
While, indeed, it is much easier for an audience to feel more of such "catharsis" for Brutus or for Romeo and Juliet or King Lear, there must be some of this feeling for Macbeth if Shakespeare is to fulfill the definition of tragedy. So, there does seem to be a compassion for Macbeth when Lady Macbeth dies and he ponders the futility of life in his soliloquy in which he depicts life as "a tale told by an idiot, signifying nothing." And, there is pity in the audience that contemplates the potential of such a brave warrior as Macbeth, who vanquished his enemies and was loved by his king; certainly, one senses the waste of such a leader who was seduced by the preternatural world.
We must always pity those who have had the potential for greatness but, being exigent, have sacrificed it for the temptations of immediacy.
To me, it is mostly revulsion and very little pity. I think that is because we do not see much of a human side to Macbeth in the play.
Really most of what we see of him is violent. He is in battle, killing people (not bad, but not something that will make us love him). Then he hears the prophecy and starts killing people.
So I guess you can pity him for being too weak to resist temptation. But mainly he revolts me because he is so willing to kill to advance himself.